Tibial Spine Avulsion Fractures in Paediatric Patients: A Systematic Review and Meta-Analysis of Surgical Management

Background: Tibial spine avulsion fractures (TSAFs) account for approximately 14% of anterior cruciate ligament injuries. This study aims to systematically review the current evidence for the operative management of paediatric TSAFs. Methods: A search was carried out across four databases: MEDLINE, Embase, Scopus, and Google Scholar. Studies discussing the outcomes of the surgical management of paediatric TSAFs since 2000 were included. Results: Of 38 studies included for review, 13 studies reported outcomes of TSAF patients undergoing screw fixation only, and 12 studies used suture fixation only. In total, 976 patients underwent arthroscopic reduction and internal fixation (ARIF), and 203 patients underwent open reduction and internal fixation (ORIF). The risk of arthrofibrosis with the use of ARIF (p = 0.45) and screws (p = 0.74) for TSAF repair was not significant. There was a significantly increased risk of knee instability (p < 0.0001), reoperation (p = 0.01), and post-operative pain (p = 0.007) with screw fixation compared to sutures. Conclusions: While the overall benefits of sutures over screws and ARIF over ORIF are unclear, there is clear preference for ARIF and suture fixation for TSAF repair in practice. We recommend large-scale comparative studies to delineate long-term outcomes for various TSAF fixation techniques.


Introduction
Tibial eminence fractures (TEFs), also referred to as tibial spine avulsion fractures (TSAFs) and anterior cruciate ligament (ACL) avulsion fractures, have been defined as bony avulsions of the ACL from its point of insertion on the intercondylar eminence of the tibia [1].These injuries are most common in skeletally immature paediatric patients, accounting for approximately 14% of ACL injuries across paediatric and adult populations overall [2].
TSAFs are commonly sports-related injuries, with higher occurrence in sports such as cycling and skiing.The higher occurrence rates in children have been attributed to many causes, including the greater degree of elasticity in ligaments of young people and the weakness of incomplete ossification of the tibial eminence in relation to ACL fibres in this population [3].
TSAFs are classified in accordance with the Meyers and McKeevers (MM) classification system into type I, type II, and type III [4].This was later modified by Zaricznyj, with the addition of type IV [5].Details of this modified MM classification can be found in Table 1.Other classification systems include the Green Tuca classification, which uses a quantitative, magnetic resonance imaging (MRI)-based system to guide the treatment and management of TSAFs, as compared to plain radiograph evaluation in the MM system [6].However, both systems have shown good inter-reliability [6].[4,5].

Type Description
Type 1 Non-or minimally displaced (<3 mm) Type 2 Minimally displaced with intact posterior hinge

Type 3a
Completely displaced involving a small portion of the eminence

Type 3b
Completely displaced involving the majority of the tibial spine Type 4 Completely displaced, rotated, and comminuted There is broad consensus about the non-operative management of MM type I TSAFs, using casting and immobilization for 6-12 weeks, followed by a gradual transition to weight bearing and range of motion exercises [7].The use of operative management to treat type II fractures is controversial, with a lack of consensus.Operative management is considered for types II, III, and IV TSAFs with unsuccessful closed reduction [7].
Multiple techniques exist for the operative fixation, which include arthroscopic (ARIF) and open (ORIF) approaches.There is a lack of consensus in the literature regarding the best method of fixation.Fixation materials most commonly include sutures, K-wires, and screws.With varying degrees of complications-including arthrofibrosis, non-union, mal-union, instability, and pain-with different procedures, there is currently a lack of consensus around the indications for use of different materials and approaches [8].
This study aims to systematically review the evidence base regarding the operative management of TSAFs in a paediatric population, with a focus on various approaches, subjective and objective outcomes, and complication rates.All the reporting is in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines.

Eligibility Criteria
The following inclusion criteria were applied: (i) Studies conducted after the year 2000 (ii) assessing outcomes of surgical management (including ORIF and ARIF approaches) of TSAFs (iii) in a skeletally immature population.Literature reviews, technical notes, cadaveric studies, conference abstracts, and case reports were excluded.Studies were only included if they had a minimum of five patients.

Information Sources and Search Strategy
A literature search was carried out on 9 January 2024 across four databases, namely MEDLINE (Ovid), Embase, Scopus, and Google Scholar.The search was carried out using relevant medical subject headings (MeSH) and synonyms for the following keywords: ('Tibial' AND 'Spine' AND 'Fracture') AND 'Surgical' AND 'Paediatrics'.Further details of the search strategy can be found in Appendix A. Articles with no fully published English Language text were excluded; however, a language restriction was not applied to the search itself.Fully published articles for conference abstracts were sought and included.Reference lists of systematic and literature reviews were also searched for relevant texts for inclusion.The search results were transferred to the Rayyan systematic review software for de-duplication and screening [9].

Selection Process
Following removal of duplicates, all search results were screened by two independent reviewers in two stages: (i) title and abstract stage, (ii) full manuscript review according to pre-defined inclusion and exclusion criteria.Reviewers were blinded to each other's decisions during the screening process.Decisions were adjudicated at the end of each stage, and any discrepancies were resolved through discussion and consensus in the presence of a third reviewer.

Data Collection Process and Data Items
To ensure standardization of the data collection process, a data extraction form was designed.Data was extracted under the following domains: (i) Study characteristicsstudy design, author conflicts of interest, year of publication, country of origin, and level of evidence; (ii) Participant characteristics-number of participants, mean age, MM classification of fracture, surgical technique used, materials used, mean follow-up time; and (iii) Outcomes-pre-and post-surgery outcome scores (including the International Knee Documentation Committee (IKDC) scores and Lysholm scores).Data was independently extracted from the included texts simultaneously by two reviewers.Upon completion, agreement between reviewers was checked through discussion in the presence of an adjudicator and consensus was reached following any discrepancies.

Study Risk of Bias Assessment
The quality of studies was assessed using the Methodological Index for Non-Randomized Studies (MINORS) criteria for non-randomized studies [10].All quality assessment was conducted by two independent reviewers.The reviewers were blinded to each other's decisions until completion.Upon completion, concordance was checked between reviewers, and any discrepancies were resolved by discussion in the presence of a third adjudicator.

Data Synthesis and Measures of Effect
Data was presented in the form of four tables, namely: (i) Study Characteristics, (ii) Critical Appraisal, (iii) Population Characteristics, and (iv) Outcomes.Analysis of data was presented narratively.Statistical analysis was conducted using a random-effects model, with the use of Odds Ratios (OR), 95% Confidence Intervals (95% CI), and p values.A random effects model was used to control for unobserved heterogeneity.A p value of <0.05 was determined to be statistically significant.All statistical analysis was done using RevMan v 5.4.1.

Heterogeneity and Subgroup Analysis
Heterogeneity was measured using the I 2 statistic, where an I 2 of 0%, 25%, 50%, and 75% correspond to no, low, moderate, and high levels of heterogeneity, respectively.

Search Results and Study Characteristics
The process of selection and inclusion of studies has been detailed in Figure 1.Of 2845 studies initially retrieved from the database search, 1906 studies were included for title and abstract screening after de-duplication.A total of 261 studies were screened by full text for inclusion within the study, of which 38 studies were found eligible for inclusion.The characteristics of the included studies have been detailed in Table 2.

Critical Appraisal
The quality of evidence was generally low.The main reasons for this include the retrospective nature of studies, the lack of control groups, and short follow-up periods.Studies also failed to calculate prospective sample sizes.The MINORS critical appraisal has been reported in Table 3. 1 Items 9-12 were only considered for comparative studies.Studies with no comparison group were critically appraised using items 1-8 only. 2 The maximum MINORS score was 16 for non-comparative studies and 24 for comparative studies. 3NA = Not Applicable.

Screw vs. Suture Risk of Arthrofibrosis
After pooling the outcomes of the studies comparing screw and suture interventions [12,14], the results revealed an increased risk of screw fixation over suture fixation for development of arthrofibrosis however, this did not reach the threshold for statistical significance (OR [95% CI] = 1.18 [0.45, 3.15], p = 0.74).A representation of this can be seen in Figure 2.

Screw vs. Suture Risk of Reoperation
After pooling the outcomes of the studies comparing screw and suture interventions [14,22], the results revealed a significantly increased risk of screw fixation over suture fixation for reoperation (OR [95% CI] = 2.81 [1.23, 6.40], p = 0.01).A representation of this can be seen in Figure 3.

Screw vs. Suture Risk of Post-Operative Pain
After pooling the outcomes of the studies comparing screw and suture interventions [12,22], the results revealed a significantly increased risk of screw fixation over suture fixation for post-operative pain (OR [95% CI] = 28.75 [2.45, 337.10], p = 0.007).A representation of this can be seen in Figure 4.

Screw vs. Suture Risk of Reoperation
After pooling the outcomes of the studies comparing screw and suture interventions [14,22], the results revealed a significantly increased risk of screw fixation over suture fixation for reoperation (OR [95% CI] = 2.81 [1.23, 6.40], p = 0.01).A representation of this can be seen in Figure 3.

Screw vs. Suture Risk of Reoperation
After pooling the outcomes of the studies comparing screw and suture interventions [14,22], the results revealed a significantly increased risk of screw fixation over suture fixation for reoperation (OR [95% CI] = 2.81 [1.23, 6.40], p = 0.01).A representation of this can be seen in Figure 3.

Screw vs. Suture Risk of Post-Operative Pain
After pooling the outcomes of the studies comparing screw and suture interventions [12,22], the results revealed a significantly increased risk of screw fixation over suture fixation for post-operative pain (OR [95% CI] = 28.75 [2.45, 337.10], p = 0.007).A representation of this can be seen in Figure 4.After pooling the outcomes of the studies comparing screw and suture interventions [12,22], the results revealed a significantly increased risk of screw fixation over suture fixation for post-operative pain (OR [95% CI] = 28.75 [2.45, 337.10], p = 0.007).A representation of this can be seen in Figure 4.

Screw vs. Suture Risk of Post-Operative Pain
After pooling the outcomes of the studies comparing screw and suture interventions [12,22], the results revealed a significantly increased risk of screw fixation over suture fixation for post-operative pain (OR [95% CI] = 28.75 [2.45, 337.10], p = 0.007).A representation of this can be seen in Figure 4.

Discussion
We present a systematic review of the literature discussing outcomes of ORIF and ARIF techniques for the fixation of paediatric TSAFs using suture and screw materials.TSAFs are increasingly common injuries in adolescents.If left untreated, they can result in significant pain and deformity, with further complications of non-union and malunion [49].As can be seen across all these studies, the complication rate is low, and good outcomes have been reported with all methods of fixation.There has been a general trend towards arthroscopic management, as evidenced by the current literature.This has several key advantages.First, there is reduced soft tissue dissection, which may facilitate an earlier range of motion and reduced post-operative pain.The second and perhaps most important advantage is the ability to perform a thorough inspection of the knee joint.In Shimberg et al.'s study, 7% of patients who underwent preoperative MRI had further in-

Discussion
We present a systematic review of the literature discussing outcomes of ORIF and ARIF techniques for the fixation of paediatric TSAFs using suture and screw materials.TSAFs are increasingly common injuries in adolescents.If left untreated, they can result in significant pain and deformity, with further complications of non-union and malunion [49].As can be seen across all these studies, the complication rate is low, and good outcomes have been reported with all methods of fixation.There has been a general trend towards arthroscopic management, as evidenced by the current literature.This has several key advantages.First, there is reduced soft tissue dissection, which may facilitate an earlier range of motion and reduced post-operative pain.The second and perhaps most important advantage is the ability to perform a thorough inspection of the knee joint.In Shimberg et al.'s study, 7% of patients who underwent preoperative MRI had further injuries identified during fixation [50].There are other studies that have called into question

Discussion
We present a systematic review of the literature discussing outcomes of ORIF and ARIF techniques for the fixation of paediatric TSAFs using suture and screw materials.TSAFs are increasingly common injuries in adolescents.If left untreated, they can result in significant pain and deformity, with further complications of non-union and malunion [49].As can be seen across all these studies, the complication rate is low, and good outcomes have been reported with all methods of fixation.There has been a general trend towards arthroscopic management, as evidenced by the current literature.This has several key advantages.
First, there is reduced soft tissue dissection, which may facilitate an earlier range of motion and reduced post-operative pain.The second and perhaps most important advantage is the ability to perform a thorough inspection of the knee joint.In Shimberg et al.'s study, 7% of patients who underwent preoperative MRI had further injuries identified during fixation [50].There are other studies that have called into question the under-sensitivity of MRI in paediatric cases.Kocher et al. found MRI had a sensitivity of 71% in partial ACL ruptures in adolescents [51].In a larger cohort study in 2022, Dawkins et al. reported MRI scanning had moderate diagnostic ability to predict meniscal injuries with associated ACL ruptures in adolescents [52].The performance was particularly poor with lateral meniscal tears (51% sensitivity).This is contrary to the original dogma, which states that MRI is a highly sensitive study for soft tissue near injuries.It appears true that, when ACL or meniscal injuries are present in isolation, MRI is highly sensitive and specific, but the diagnostic accuracy declines in cases where concomitant injuries are present [53].The sensitivity declines to around 50-75% [52,[54][55][56].This could have significant implications for management.ARIF would therefore facilitate adequate inspection of the joint prior to proceeding with fixation.While concomitant injuries can be identified with an open approach, diagnostic arthroscopy would likely facilitate more thorough inspection of the joint, particularly the posteromedial and posterolateral corners.What remains unclear from the literature is whether these missed injuries would have significantly impacted the outcomes.However, diagnostic accuracy does remain a priority, and we would certainly recommend preoperative MRI in all cases, especially where the treating surgeon is planning an open approach.While it can be argued that MRI is not necessary in ARIF, we would still advise it for two reasons.First, MRI can facilitate operative planning.Second, MRI has the potential to demonstrate extension of the fracture line into the tibial plateau, which can often be missed on plain radiographs [57].
There was no clear difference in the overall complications between arthroscopic and open approaches.The traditional concern of increased risk of arthrofibrosis with ARIF appears to be unfounded.In Watts et al.'s study, prolonged time to surgery was the more significant factor in the development of arthrofibrosis [41].This is perhaps more likely to occur in cases of ARIF, as there may be a delay until a surgeon with the appropriate skill set becomes available.Early range of motion is also important in preventing ongoing stiffness and should be encouraged post-operatively, where appropriate [58].While ARIF provides a minimally invasive approach to fixation, along with shorter hospital stays and lower risks of infection, the surgical outcomes between ORIF and ARIF techniques remain similar.Hence, the choice of fixation technique would be heavily reliant on the experience of the surgeon.Suture vs. screw fixation is the other key controversy in management.This review demonstrated a higher overall complication risk with screw fixation-reoperation rates were higher due to the need for metalware in screw fixation.Screw fixation can increase the risk of anterior impingement and can damage the femoral notch, but this can be mitigated with the use of a bioabsorbable screw [59].From the studies in the review, it appears that arthroscopic suture fixation is the most common practice.Suture fixation has been shown to be biomechanically superior to screw fixation when considering the cyclical loads the knee is subjected to [60].However, there was no difference in load required for overall failure [60].While there is no clinical evidence to suggest one method is superior to the other with respect to fracture healing and overall outcomes, suture fixation has several additional advantages.First, sutures can be used for more comminuted MM type IV injuries; the degree of comminution may have been underestimated in preoperative imaging [60].Second, there is a theoretical increased risk of physeal damage with screw placement, which could lead to growth arrest [50].An all-epiphyseal approach to fixation is essential to avoid growth arrest.A review by Osti et al. also highlighted the controversy between choice of screw versus suture fixation, with screws allowing for more early mobilization and weight bearing compared to sutures [61].However, the potential to treat small and comminuted fractures with sutures, while avoiding risks of reoperation and impaired bone growth, underlines the need to consider a risk-benefit ratio while choosing fixation materials.
This review was limited by the retrospective nature of the studies, the lack of adequate control groups in many of the studies, and the short overall follow-up.In addition, many studies had low patient numbers.This limited the depth of the meta-analysis possible.However, it is clear that TSAFs have a good prognosis if treated well, regardless of the operative approach or fixation method.We would advocate preoperative MRI in all cases, and arthroscopic suture fixation where possible, as it will allow for the most thorough inspection of the joint, and suture fixation offers superior biomechanical support and greater versatility along with a lower risk of impingement.However, we would caveat this by emphasising that all recognised approaches appear to give good outcomes with low risk of complications when performed well, and the treating surgeon should perform the procedure that best matches their skillset.

Conclusions
Overall, good outcomes are reported in TSAFs regardless of the approach or surgical fixation.There is no clear evidence to advocate one method of fixation over another.However, we would recommend arthroscopic suture fixation due to the diagnostic utility of arthroscopy and the biomechanical superiority of suture fixation.Preoperative MRI scans are essential in all cases of operative management, but surgeons should be cognisant of the limitations of MRI.Further evidence is needed to investigate the long-term outcomes and evaluate the significance of concomitant injuries that may be present.

Figure 1 .
Figure 1.PRISMA Flow Diagram for Systematic Reviews.Summary of search screening progress.

Figure 1 .
Figure 1.PRISMA Flow Diagram for Systematic Reviews.Summary of search screening progress.

Children 2024 ,
11, x FOR PEER REVIEW 18 of 23 development of arthrofibrosis however, this did not reach the threshold for statistical significance (OR [95% CI] = 1.18 [0.45, 3.15], p = 0.74).A representation of this can be seen in Figure 2.

Children 2024 ,
11, x FOR PEER REVIEW 18 of 23 development of arthrofibrosis however, this did not reach the threshold for statistical significance (OR [95% CI] = 1.18 [0.45, 3.15], p = 0.74).A representation of this can be seen in Figure 2.

7 .
Screw vs. Suture Risk of Post-Operative Pain

Children 2024 ,
11, x FOR PEER REVIEW 19 of 23

Children 2024 ,
11, x FOR PEER REVIEW 19 of 23

Table 1 .
Overview of Meyers and McKeever Classification System

Table 2 .
Study characteristics table.

Table 2 . Cont. (Author, Year of Publication) Title of Paper Country of Origin Journal of Publication Level of Evidence
(Zheng et al., 2021) [47] Arthroscopically Assisted Cannulated Screw Fixation for Treating Type III Tibial Intercondylar Eminence Fractures: A Short-Term Retrospective Controlled Study China Frontiers in Surgery 3 (Zhou et al., 2023) [48] Arthroscopic percutaneous pullout suture transverse tunnel technique repair for tibial spine fractures in skeletally immature patients China International Orthopaedics 3 Children 2024, 11, x FOR PEER REVIEW 4 of 23

Table 2 .
Study characteristics table.
(Author, Year of Publication) Title of Paper Country of Origin Journal of Publication Level of Evidence Neglected ununited tibial eminence fractures in